Effects of Feeding Frequency and Dietary Protein/Carbohydrate Ratios on Gilthead Seabream (Sparus aurata) Intestinal Functionality and Health

Abstract

The present study evaluated the effects of feeding frequency (FF) and dietary protein/carbohydrate (P/CH) ratios on intestinal histomorphology, microbiota profile, and digestive and oxidative stress-related enzyme activities of gilthead seabream (Sparus aurata). To this purpose, two practical diets were formulated: one with 50% P and 10% CH (P50/CH10) and other with 40% P and 20% CH (P40/CH20). Triplicate groups of fish with 9.1 ± 0.01 g were fed these diets for 60 days until visual satiation at a FF of 1, 2, or 3 meals per day. Distal intestine histomorphology was not affected by diet composition or FF. However, the pyloric caeca (PC) of fish fed 1 meal per day presented more gut fold height alterations than the other groups, except in fish fed diet P50/CH10 3 meals per day, where no changes was observed. Fish fed diet P40/CH20 3 meals per day also presented higher PC submucosa cellularity than the other groups. Fish fed diet P40/CH20 presented a higher number of operational taxonomic units, microbial richness, and diversity indices than fish fed diet P50/CH10. Amylase was the only measured digestive enzyme affected by the experimental conditions, presenting higher activity in fish fed diet P50/CH10 once per day. Glucose-6-phosphate dehydrogenase activity was lower in fish fed 2 meals per day than only 1. While catalase activity was lower in fish fed 2 than 3 meals per day. Glutathione reductase activity was the only measured parameter affected both by dietary P/CH ratio and FF, being inferior in fish fed once per day the P50/CH10 diet than the P40/CH20 diet and, also in the P50/CH10 diet, to fish fed 1 than those fed 3 meals per day. Overall, no major interactions was observed between dietary P/CH ratio and FF; however, a P40/CH20 diet fed 2 meals per day might be recommended for gilthead seabream juveniles.

Efecto de la frecuencia de alimentación en la respuesta alimenticia del Camarón Blanco del Pacífico (Litopenaeus Vannamei)

“…Los efectos del procesamiento de peletización y extrusión sobre el crecimiento de diferentes animales acuáticos son contradictorios; el proceso de extrusión mejora el crecimiento y la utilización del alimento para la trucha arco iris (Glencross y Turchini, 2011); dorada Sparus Aurata (Basto-Silva et al, 2022;Venou et al, 2009) perca plateada Carassius gibelio (Booth et al, 2002), tilapia Oreochromis niloticus (Amirkolaie et al, 2006;Kanmani et al, 2018), y carpa Cyprinus carpio (Gao et al, 2019); sin embargo, se encontró un crecimiento esencialmente similar en el bagre de canal Ictalarus punctatus (Xu et al, 2017).…”